Gastrointestinal implant with drawstring

ABSTRACT

A gastrointestinal implant device includes a flexible, floppy sleeve, open at both ends, that extends into the duodenum. The device further includes a collapsible anchor coupled to the proximal portion of the sleeve. The device further includes a drawstring that is threaded through a proximal end of the anchor, and barbs that extend from the exterior surface of the anchor. The collapsible anchor can be a wave anchor. The drawstring can be used to collapse at least a proximal portion of the implant device. This is useful in removing or repositioning the implant device.

RELATED APPLICATION

This application is a continuation-in-part of U.S. application Ser. No.11/318,083, filed Dec. 22, 2005, which claims the benefit of U.S.Provisional Application No. 60/663,352, filed Mar. 17, 2005; and is acontinuation-in-part of U.S. application Ser. No. 10/858,851, filed Jun.1, 2004, which claims the benefit of U.S. Provisional Application Nos.60/544,527, filed Feb. 13, 2004 and 60/528,084, filed Dec. 9, 2003. Theentire teachings of the above application are incorporated herein byreference.

BACKGROUND OF THE INVENTION

Gastrointestinal sleeves can be used to treat obesity or diabetes. Tokeep the sleeve in place, an anchoring device is needed. Anchoring caninclude stents or conventional surgical techniques, such as sutures,staples, surgical adhesives, and others. At least some anchoring devicesuse an interference fit, placing an implant device having a relaxeddiameter larger than the diameter offered by the intestine. Otheranchoring devices may include barbs that are adapted to penetrate intothe surrounding muscular tissue of the gastrointestinal tract.

Often, these gastrointestinal sleeves, due to the complex structure ofthe anchoring device, may not be removed without damaging surroundingtissue, unless by resection.

SUMMARY OF THE INVENTION

The present invention relates to gastrointestinal devices, methods, andapparatus for removing and/or repositioning the gastrointestinal devicesfrom a natural bodily lumen. In certain embodiments, a gastrointestinalimplant includes a flexible, floppy sleeve. The sleeve is open at bothends and extends into the duodenum, preferably at least one foot. Theimplant also includes a collapsible anchor that is coupled to theproximal portion of the sleeve. The implant can further include adrawstring that is threaded through a proximal end of the anchor.Finally, the implant can include rigid barbs at a fixed angle extendingfrom the exterior surface of the anchor.

In certain embodiments, the anchor includes interconnected struts. Thesleeve can have a webbing material at the proximal portion of thesleeve, where the webbing material is coupled to the struts. Thedrawstring can be woven through holes in the webbing material.

In certain embodiments, the drawstring can be woven over and under thestruts through a single hole between the struts. The implant can alsoinclude a second drawstring. The second drawstring can be woven througha single hole over and under the struts. Alternatively, the seconddrawstring can also be woven through pairs of holes in the webbingmaterial. In one embodiment, the anchor is a wave anchor.

A method for repositioning (including removal of) a gastrointestinalimplant is also described. The method includes first engaging adrawstring that is disposed on the implantable device. At least aproximal portion of the device is collapsed by pulling on thedrawstring. Finally, the device is moved within the natural bodilylumen. The device can also be removed from the patient's body ifdesired.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

FIG. 1 shows an exemplary embodiment of a repositioning device;

FIGS. 2A-2F are a series of schematic diagrams showing an exemplaryembodiment of the invention capturing a proximal portion of animplantable device for repositioning;

FIGS. 3A-3F are another series of schematic diagrams showing anexemplary embodiment of the invention retrieving an implantable devicein the intestine;

FIGS. 4A-4B show an alternative embodiment of the invention using arotary actuator;

FIG. 5 shows an alternative embodiment using a rat-tooth grasper;

FIGS. 6A-6C show an alternative embodiment of a retrieval hood; and

FIGS. 7A and 7B show an endoscope used to view the repositioningprocess.

FIGS. 8A-8B show an alternative embodiment of a grasper;

FIG. 9A illustrates an embodiment of a gastrointestinal device with awave anchor and drawstrings;

FIG. 9B-9D shows an alternative embodiment of the gastrointestinalimplant device of FIG. 9A;

FIGS. 10A-10B show an embodiment of the gastrointestinal device with thedrawstrings of FIG. 9A;

FIGS. 11A-11B show an alternate embodiment of the gastrointestinalimplant device with the drawstrings of FIG. 9B; and

FIGS. 12A-12D show an embodiment of barbs on a gastrointestinal implantdevice.

DETAILED DESCRIPTION OF THE INVENTION

A description of preferred embodiments of the invention follows.

Gastrointestinal implants can be used for a number of treatments, atleast some of which are described in U.S. Pat. No. 7,025,791B2, filed onJan. 9, 2003, that claimed the benefit of U.S. Provisional Application60/430,320 filed on Dec. 2, 2002, and incorporated herein by referencein its entirety. Implants placed within the gastrointestinal tract aretypically subject to substantial mechanical forces related to thedigestion process. For example, an implant placed within the intestine,distal to the pyloric sphincter, will be subjected to peristaltic forcestending to push and pull the implant along the intestine. To keep theimplant in place, an anchoring device is required. Anchoring can includeconventional surgical techniques, such as sutures, staples, surgicaladhesives, etc. Anchoring within the intestine, however, poses a uniqueset of challenges. At least some anchoring devices use an interferencefit, placing an implant device having a relaxed diameter larger than thediameter offered by the intestine. Other anchoring devices use barbsthat are adapted to penetrate into the surrounding muscular tissue ofthe gastrointestinal tract. Examples of anchors used for anchoringimplants are described in U.S. patent application Ser. No. 10/858,852filed on Jun. 1, 2004, claiming the benefit of U.S. ProvisionalApplication No. 60/528,084 filed on Dec. 9, 2003, and U.S. ProvisionalApplication No. 60/544,527, filed on Feb. 13, 2004, all incorporatedherein in their entireties by reference.

Anchors relying on interference fit, barbs, or a combination of bothtypically have relaxed dimensions greater than the normal open diameterof the intestine (e.g., greater than twenty five millimeters in an adulthuman). For example, the implant may be delivered to the intendedlocation in a compressed state using a catheter having an internaldiameter of only about 12 millimeters. When the implant is deployedwithin the intestine it expands to its implanted size. For example, toplace an implant into the proximal duodenum, a catheter can be insertedthrough the patient's nose or mouth, through the esophagus, stomach andpyloric sphincter. The implanted devices can be compressed again priorto and/or during repositioning or removal.

One embodiment of removing or repositioning a gastrointestinal implantdevice is shown in FIG. 1. The repositioning device 100 may include ahandle 110 supporting an actuator 120. The repositioning device 100further may include an elongated member 150, such as a wire. Theelongated member 150 is slidably disposed within the handle 110. Theactuator 120 is adapted to attach to a proximal end of the elongatedmember 150. The repositioning device 100 further may include an innertube 140. The inner tube 140 defines a lumen within which the elongatedmember 150 is slidably disposed. The inner tube 140 is adapted forinsertion into a natural bodily lumen through an endoscope workingchannel or a catheter. The inner tube 140 is fixed to a distal end ofthe handle 110.

A grasper 160, a hook in this embodiment, is coupled at a distal end ofthe elongated member 150 and is adapted to grasp a feature of animplantable device. For example, a drawstring as described in FIG. 11,is provided on some implantable devices such that manipulation of thedrawstring can reduce at least one dimension (e.g., the diameter) of theimplantable device.

The elongated member 150 slidably fits through a hole within the handle110, and is attached to the actuator 120. The actuator 120 and thehandle 110 may be operated manually from a site external to a body. Forexample, the handle 110 and the actuator 120 can be used to maneuver theelongated member 150 and grasper 160 disposed at the distal end of theelongated member 150. The handle 110 may also be manually manipulated tomaneuver the inner tube 140.

The elongated member 150 may be several feet in length. Preferably, theelongated member 150 is formed of a flexible material to facilitatenavigation through a medical instrument, for example, through theworking channel of an endoscope within a natural bodily lumen. Further,the elongated member 150 should be composed of a biocompatible material.Such materials may include polymers and certain metals, such as Nitinolor stainless steel. The elongated member 150 is coupled at its distalend to the grasper 160.

In some embodiments, the grasper 160 may be a hook. The grasper 160 isattached to the distal end of the elongated member 150. The grasper 160may be any means of grasping a drawstring of an implantable device. Thegrasper 160 may be attached to the elongated member 150 by variousmechanical, chemical, welding or bonding means. The grasper 160 may beformed of a biocompatible material such as polymers and metals such asNitinol or stainless steel. In one embodiment, the distal end of theelongated member 150 is shaped to form a hook.

The grasper 160 attached to a distal portion of the elongated member150, is disposed within a lumen of the inner tube 140. The inner tube140 may be several feet in length in order to extend from a proximalportion of an implantable device to outside of a body. The dimensions ofthe inner tube may be such that it adapts to the working channel of anendoscope. The inner tube 140 may be made of a biocompatible andflexible material such as certain polymers. Such polymers may includesilicone, polyurethane, polyethylene and certain low frictionfluoropolymer materials such as PTFE, PFA or FEP. In one embodiment, thegrasper 160 is coupled to a grasper locking mechanism 155 through theelongated member 150. The grasper locking mechanism 155 is disposed at aproximal portion of the elongated member 150. The grasper lockingmechanism 155 locks in place the elongated member 150 coupled to thegrasper 160, when the grasper 160 has pulled the drawstring of theimplantable device, and the implantable device has thus been radiallycollapsed. In one embodiment, the grasper locking mechanism 155 is acompression-type locking mechanism. The grasper locking mechanism 155includes a member 155A, which is threaded onto member 155B. Member 155Bis adapted to be fixed within a proximal opening of the handle 110. Theelongated member 160 is slidably disposed through the grasper lockingmechanism 155, when the grasper locking mechanism 155 is left unlocked.When the grasper 160 has grasped the collapsed implantable device, thegrasper locking mechanism 155 may be locked, thus tightening around theelongated member 150 so that the elongated member 160 is fixed and is nolonger slideable within the inner tube 140. In other embodiments, thegrasper 160 coupled to the elongated member 150 may be locked usingother locking mechanisms such as other types of compression locks,screw-type locks, pincher type locks, clamp type locks or any meanscapable of locking the grasper 160 coupled to the elongated member 150in place. Example locking devices and methods of using locking devicesare described in U.S. patent application Ser. No. 11/318,086, filed onDec. 22, 2005, incorporated herein by reference in its entirety.

In one embodiment, the actuator 120 may be manually operated bymaneuvering the actuator 120 from a site external to a body. Theactuator 120 may include one or more features adapted for manualmanipulation. For example, the actuator may include one or more loopedelements adapted to be operated by fingers and/or thumb. The actuator120 may advance the elongated member 150 distally by pushing on theactuator 120 by grasping the looped element and pushing it. The actuator120 may be used to proximally draw the elongated member 150 by graspingand pulling of the looped element. In other embodiments, the actuatormay be any means capable of advancing distally or pulling proximally theelongated member 150 coupled to the grasper 160.

The repositioning device 100 may further include an outer tube 130. Theouter tube 130 also defines a lumen within which the inner tube 140 maybe slidably disposed. In one embodiment, the outer tube 130 is aninsertion tube of an endoscope. For example, if the repositioning device100 is being used within the gastrointestinal tract, the endoscope maybe a gastroscope, such as the Olympus GID Q160, 9.8 mm OD. The endoscopemay permit the operator to view the removal or repositioning process ofthe implantable device and to manipulate the relevant features of boththe repositioning device 100 and the implantable device during theremoval or repositioning process. The positioning and movement of theendoscope may be accomplished by manually maneuvering the proximal endof the endoscope from a site external to the body.

Alternatively, the outer tube 130 may be a separate tube from anendoscope, wherein an endoscope may be place adjacent to therepositioning device 100 in order to view and manipulate therepositioning and/or removal process of the implantable device. Thepositioning of the outer tube 130 may be accomplished from a siteexternal to the body. The positioning of the outer tube 130 may bemanual, for example, by an operator maneuvering a proximal end of theouter tube 130.

In some embodiments, the repositioning device 100 may also include aretrieval hood 190. The retrieval hood 190 may be attached to a distalend of the outer tube 130. The retrieval hood 190 is adapted to captureat least a proximal portion of the implantable device. In someembodiments, the retrieval hood 190 is coupled to the outer tube 130using an interference fit, where the diameter of the proximal end of theretrieval hood 190 is slightly larger than the distal end of the outertube 130. In other embodiments, the retrieval hood 190 may be coupled tothe outer tube 130 using alternative mechanical, chemical, or bondingtechniques.

The retrieval hood 190 may generally be conical in shape. The retrievalhood 190 has openings at both a proximal end and a distal end. As shown,the distal end of the retrieval hood 190 may be flared to facilitatecapture of an implantable device to be repositioned. In someembodiments, the retrieval hood 190 is made of a flexible material tofacilitate its atraumatic placement within a body and to betteraccommodate at least the proximal portion of the implantable deviceprior to repositioning. The retrieval hood 190 may be made of atransparent, biocompatible rigid plastic such as polycarbonate or aflexible polymer such as polyurethane, PVC or silicone.

The additional visibility offered by the transparent retrieval hood 190may be beneficial to the repositioning procedure. For example, if therepositioning device 100 is used through the working channel of anendoscope, (when the endoscope is the outer tube 130) the transparentretrieval hood 190 may allow for a wide field of view. Alternatively, atransparent retrieval hood 190 may also allow for easier viewing from anendoscope external to the repositioning device 100.

The repositioning device 100 may include a retrieval locking mechanism195. In one embodiment, the retrieval locking mechanism 195 is apincher-type lock. The retrieval locking mechanism 195, which isslideable upon the inner tube 140 is positioned at the proximal end ofthe outer tube 130, on the inner tube 140. Once the retrieval hood 190is advanced over the implantable device to capture it, the pincher-typeretrieval locking mechanism 195 is then pinched on the inner tube 140.The inner tube 140 with the elongated member 150 disposed therein isthus locked into place with respect to the outer tube 130 and theretrieval hood 190. This prevents inadvertent release of theradially-collapsed implantable device. In other embodiments, the innertube 140 and elongated member 150 may be locked with respect to theretrieval hood 190 using other locking mechanisms such as compressionlocks, other screw-type locks, pincher-type locks, clamp-type locks orany means capable of locking the inner tube 140 and elongated member 150in place.

The retrieval locking mechanism 195 is beneficial in preventing damageto surrounding tissue when the implantable device is removed orrepositioned in the natural bodily lumen. If the inner tube 140 andelongated member 150 are not locked with respect to the retrieval hood190, the implantable device captured within the retrieval hood 190 mayrelease, thereby moving distal to the retrieval hood 190 allowing it toexpand and exposing anchoring barbs to the tissues. Thus, when theimplantable device is removed or repositioned within the natural bodilylumen, the exposed and expanded implantable device would be draggedwithin the natural bodily lumen, resulting in possible tissue damage.

A method of using the repositioning device 100 to capture at least aproximal portion of an implantable device 270 for repositioning andremoval is shown in FIGS. 2A-2F. As shown in FIG. 2A, the grasper 160coupled to the distal end of the elongated member 150, is advancedtowards a drawstring 280 positioned on the proximal end of theimplantable device 270 by pushing on the actuator 120 (as indicated byarrow I.) Details of the drawstring are shown in FIG. 11. The distal endof the grasper 160 can extend distally beyond the outer tube 130, theretrieval hood 190, and the inner tube 140.

As shown in FIG. 2B, the grasper 160 extending distally beyond the innertube 140, engages a portion of the drawstring 280 of the implantabledevice 270. The actuator 120 is then used to proximally draw the grasper160 and the engaged portion of the drawstring 280 (as indicated by arrowII).

As shown in FIG. 2C, the grasper 160 and the engaged portion of thedrawstring 280 are drawn proximally into the distal end of the innertube 140, reducing slack in the drawstring 280. The inner tube 140 withthe grasper 160 and the engaged drawstring 280 disposed in it distalend, is then advanced distally (indicated by the direction of arrowIII). The distal advancement of the inner tube 140 may be accomplishedby manipulating the handle 110 coupled to the inner tube 140.

As shown in FIG. 2D, the inner tube 140 is advanced distally until it iswithin an interior portion of the implantable device 270, or beyond theproximal plane of the implantable device 270 (as indicated by arrow IV).

As shown in FIG. 2E, once the inner tube 140 is positioned within theinterior of the implantable device 270, the actuator 120 is proximallypulled so that the grasper 160 coupled to the elongated member 150 pullsthe engaged drawstring 280 proximally into the inner tube 140 (asindicated by arrow V). When the engaged drawstring 280 is pulled by thegrasper 160, the engaged drawstring 280, is also drawn within the lumenof the inner tube 140 sufficiently to radially collapse the implantabledevice 270, thereby detaching it from the surrounding anatomy. Forexample, as previously described, some implants include an anchor orstent having barbs 275 adapted to pierce the surrounding muscular tissueof the intestine. As the drawstring 280 is withdrawn, the anchor orstent is collapsed radially until the barbs 275 are dislodged from thesurrounding tissue. At least a proximal portion of the implantabledevice 270, is therefore radially collapsed.

The positioning of the inner tube 140 coupled to the grasper 160 withinthe interior of the implantable device 270, is advantageous inpreventing damage to surrounding tissue within the natural bodily lumen.As the engaged drawstring 280 is pulled proximally into the inner tube140, the implantable device 270 is radially collapsed, thereforeavoiding significant axial pull on the drawstring 280. This avoidsunnecessary dragging of the implantable device 270 through the naturalbodily lumen, thus decreasing the chances of tissue damage cause by theexposed barbs 275.

Once the implantable device 270 has been sufficiently radially collapsedby the grasper 160, the elongated member 150 is locked into place by thegrasper locking mechanism 155. The elongated member 150 is thus, nolonger slideable within the inner tube 140 and the handle 110, but isfixed. The elongated member 150 remains fixed until the grasper lockingmechanism 155 is unlocked.

As shown in FIG. 2F, once the implantable device 270 is sufficientlycollapsed and locked into place by the grasper locking mechanism 155,the outer tube 130 coupled to the retrieval hood 190 is advanceddistally over the inner tube 140 and the radially-collapsed implantabledevice 270 (as indicated by arrow VI). As the retrieval hood 190 isadvanced, it preferably captures at least a proximal portion of theimplantable device 270. If the outer tube 130 is an insertion tube of anendoscope, the proximal portion of the endoscope may be manuallymaneuvered from a site outside of the body in order to centralize thecollapsed implantable device 270 within the flared distal end of theretrieval hood 190. Similarly, if the outer tube 130 is a tube distinctfrom an endoscope, such as a catheter, the proximal end of the outertube 130 may be maneuvered manually and/or from a site external to thebody.

Advancing the retrieval hood 190 over the implantable device 270 may beadvantageous in avoiding damage to surrounding tissue. Because theretrieval hood 190 is being advanced over the implantable device 270, atleast proximally facing collapsed barbs 275 are covered and will nottraumatize the tissue within the natural bodily lumen. The distal facingbarbs 275, even if left uncovered will not penetrate into the tissue asthey are facing opposite to the direction of withdrawal (indicated byarrow V) and therefore will not cause damage to surrounding tissue. Thisfacilitates the safe removal or repositioning of the implantable device270 within the natural bodily lumen.

Once the retrieval hood 190 adequately captures the collapsedimplantable device 270, the inner tube 140 and elongated member 150 arelocked with respect to the retrieval hood 190 using the retrievallocking mechanism 195, thereby preventing the inadvertent release theimplantable device 270 and thereby exposing barbs 275. Once captured andlocked into place, the repositioning device 100 and the implantabledevice 270 can be safely removed from the body or repositioned withinthe natural bodily lumen as one unit. Another illustration of theremoval process is presented in FIGS. 3A-3F for an application within agastrointestinal tract 301. The implantable device 270 is secured orattached in the pyloric region 360 of the stomach 350 or, as shown inFIG. 3A, just distal to the pylorus 320 in the proximal portion of theduodenum 330. As shown in FIG. 3B, the repositioning device 100 isadvanced distally from the outside of a body through the esophagus (notshown) and further through the stomach 350 and the pyloric region 360 ofthe stomach 350 in order to reach the proximal portion of theimplantable device 270. Preferably, a distal portion of therepositioning device 100 is advanced through the pyloric sphincter 320extending at least partially into the proximal duodenum 330.

As shown in FIG. 3C, the inner tube 140 with the grasper 160 and theengaged drawstring 280 disposed within the distal end of the inner tube140, is advanced distally until it is within the interior, or beyond theproximal plane of the implantable device 270. The grasper 160, can thenbe pulled proximally operating the drawstring 280, thereby radiallycollapsing a proximal portion of the implantable device 270. The barbs275 of the implantable device 270 are dislodged from the surroundingtissue. Once the implantable device 270 is sufficiently collapsed, theelongated member 150 coupled to the grasper 160 can be locked into placeby locking the grasper locking mechanism (not shown) in order to preventrelease of the collapsed implantable device 270.

As shown in FIG. 3D, once the implantable device 270 has been radiallycollapsed, the outer tube 130 coupled to the retrieval hood 190 isadvanced distally in order to capture a collapsed proximal portion ofthe implantable device 270 and the dislodged barbs 275. If the outertube 130 is the insertion tube of an endoscope, the proximal portion ofthe endoscope may be maneuvered from a site external to the body inorder to center the collapsed implantable device 270 and collapsed barbs275 within the flared head of the retrieval hood 190. For example, theendoscope may be a gastroscope, such the Olympus GID Q160, 9.8 mm OD.

Similarly, if the outer tube 130 is a tube distinct from an endoscope,the proximal portion may be maneuvered to centralize the collapsedimplantable device 270 and the dislodged, collapsed barbs 275 within theflared end of the retrieval hood 190. The centralization within theretrieval hood 190, which promotes a complete capture of the proximalend of the collapsed implantable device 270 and the collapsed barbs 275by the retrieval hood 190, reduces the chances of damage to thesurrounding tissue, which may be caused by protruding barbs 275 from theretrieval hood 190, when the implantable device 270 and therepositioning devices 100 are removed from the body by being drawnproximally through the gastrointestinal tract 301 and esophagus.

Once effectively captured in the retrieval hood 190 and locked in placeby the retrieval locking device, the implantable device 270 and therepositioning device 100 may be repositioned to a different locationwithin the gastrointestinal tract 301 or removed from the body as oneunit as shown in FIGS. 3E and 3F. When removing an implantable device,this unit is proximally drawn through the esophagus in a safe manner.

Alternative embodiments are shown in FIGS. 4A and 4B, where therepositioning device 100 includes a rotary actuator 410. The rotaryactuator 410 can be used to collapse the implantable device. The rotaryactuated device 100 may similarly include the inner tube 140, theelongated member 150 and a grasper 450. Once the grasper 450 captures aportion of the drawstring of the implantable device, a rotary actuator410 spins the grasper 450 causing the drawstring to wind about thegrasper 450. In one embodiment, the grasper 450 may be a spade with anotch as shown in FIG. 4B. In other embodiments, the grasper 450 may bea hook or any means capable of engaging the drawstring. For example, thedistal end of the elongated member 150 can be shaped to form a hook asshown in FIG. 4A.

The winding action causes the drawstring to wrap about the grasper 450,thereby operating the drawstring and radially collapsing the implantabledevice. Once the implantable device has been radially collapsed theproximal portion of the implantable device can be captured by aretrieval hood when provided as previously described. The entire device100 and the implantable device may then be removed in a similar mannerto that described in FIGS. 3A-3F.

An advantage provided by the rotational device is that it is notstroke-length limited. Stroke-length refers to the length of translationprovided by the grasper within the inner tube. This translation may belimited by the physical dimensions of the device and will limit thelength of drawstring that can be withdrawn into the sleeve. There is nosimilar limitation to the amount of rotation (i.e., number of turns). Aslong as the hook and wire are capable of rotating, the number ofrotations can be varied to selectably wind a desired length of thedrawstring about the wire.

It may be possible that with a fixed stroke length, if the drawstring onthe anchor stretches, the grasper may not be able to fully collapse theanchor. Additionally, much of the force applied at the proximal end ofthe reciprocating device may be lost through the shaft as the shaftbuckles. Almost all of the torque provided at the proximal end of therotational device can be delivered to its distal end while keeping itflexible. Also, the actuation of the rotational device may provideimproved ergonomics, since it is translated separately from itsrotational motion. This may make it easier to move the drawstringcollapse point proximal or distal to dislodge the anchor or stent, whilekeeping the drawstring collapsed.

An alternative type of grasper is shown in FIG. 5, where the grasper isa rat-tooth type grasper 510. The rat tooth grasper 510 is advancedwithin the interior of the drawstring as described in previous figures.The rat tooth grasper 510 is then actuated so that its jaws 520 graspthe drawstring between the two jaws 520. The rat tooth grasper 510 isadvantageous in that the drawstring is easily released if desired bysimply opening the jaws 520 of the rat tooth grasper 510. The jaws 520are opened by advancing distally the jaws 520 until they exit the innertube 140. The jaws 520 are closed by pulling the jaws into the innertube 140.

An alternative grasper is also shown in FIG. 8A. The retrieval grasper800 includes hooks 810. The grasper also includes first extensions 820and dog legs 830. The dog legs 830 are angled out 12 degrees fromparallel with the extension 820. The hooks 810 are made with a 150degree arch sweep. As shown in FIG. 8B, the first extensions 820 stayparallel to a sheath 840 when retracted into the sheath 840, and the doglegs 830 prevent the hooks 810 from engaging the edge of the sheath 840.This type of grasper is further described in U.S. ProvisionalApplication 60/902,924, filed on Feb. 22, 2007, herein incorporated byreference in its entirety.

An alternative or additional embodiment of the repositioning device 100is show in FIG. 6A-6C, wherein the retrieval hood 190 includes a featureadapted to steer the grasper towards the center of the implanted device.As shown in the cross section in 6B and 6C, an interior ramp 640 isprovided over at least a portion of the interior of the retrieval hood190. Additionally, the retrieval hood 190 includes a flared end 650. Theproximal end of the retrieval hood 190 may be coupled to the outer tube130 or alternatively, to the distal end of an insertion tube of anendoscope.

For example, the angle of the flared end 650 can extend over about 10 to90 degrees about the interior of the retrieval hood 190 as shown in FIG.6B. The interior ramp 640 is aligned to centrally position the distalend of the inner tube 140 with the grasper 160 and engaged drawstring280 disposed therein, within the interior of the implantable deviceprior to and as it is radially collapsing the device. This may beadvantageous, because the inner tube 140 and grasper 160 tend to beeccentric, or biased towards one side since the working channel of theendoscope through which the grasper is positioned is eccentric. Distaladvancement of the inner tube 140 through the retrieval hood 190 towardsthe implanted device, allows the inner tube 140 and elongated member 150to bend towards a central position within the drawstring of theimplantable device, and pull the drawstring. This allows for primarilyuniform radial force to be applied to the drawstring in order toradially collapse the implantable device.

As the retrieval hood 190 is advanced distally to capture the radiallycollapsed device, the interior ramp 640 along with the angle of theflared end 650 allows the elongated member along with the radiallycollapsed implantable device to be centralized within the retrieval hood190, therefore facilitating the removal or repositioning of theimplantable device.

As shown in FIGS. 7A and 7B, all procedures just described can beobserved by the endoscopist using an endoscope and camera. Such a visualaid will facilitate operation of the proximal controls (e.g., handle 110and actuator 120) to position the grasper 160 near the drawstring, toengage the drawstring, to position the inner tube 140 within theinterior of the implantable device so that the implantable device may besufficiently collapsed, to confirm that the barbs are sufficientlydetached, and to capture the proximal end of the implant with theretrieval hood 190. Beneficially, the retrieval hood 190 can be formedof a transparent material, such as polycarbonate, PVC or polyurethane.Such additional visibility offered by the transparent retrieval hood 190is advantageous to the removal procedure, by allowing clear viewing ofthe repositioning procedure.

As shown in FIG. 7A, the distal end of the endoscope 700 includes anobjective lens 710, through which the repositioning procedure can beviewed. A light source 720 may be provided to enable brighter viewing ofthe repositioning procedure. An irrigation port 715 may also provided.Additionally, the distal end of the endoscope 700 may include aninstrument channel outlet 730.

As described in previous figures, the outer tube 130 may be theinsertion tube 740 of the endoscope 700 as shown in FIG. 7B. The distalend of the insertion tube 740 of the endoscope 700 may include theinstrument channel outlet 730, as shown in FIG. 7A. The inner tube 140is slidably disposed within the insertion tube 740 of the endoscope 700,and may be distally advanced or proximally pulled through the instrumentchannel outlet 730. The proximal end of an instrument channel 755 isshown. The actuator 120 and handle 110 of the repositioning device 100may be maneuvered from the instrument channel 755, through which theinner tube 140 of the repositioning device 100 is slidably disposed. Theprocedure may be viewed and directed by an endoscopist, for example,looking through an eyepiece 760 or at an image projected on a monitor.

Alternatively, the outer tube 130 may be a distinct tube from theinsertion tube 740 of the endoscope 700. In this case, if the operatorwishes to view the repositioning procedure through the endoscope 700,the endoscope 700 may be positioned adjacent to the repositioning device100 within the natural bodily lumen. The viewing and/or guiding of therepositioning procedure is facilitated by the transparent retrieval hood190.

An endoscope may be used in combination with, or independent of afluoroscope. Alternatively, fluoroscopy may be utilized to guide andview the repositioning procedure independent of endoscopy.

Fluoroscopy may be used to guide the removal or repositioning of animplantable device. The distal end of the inner tube 140 may be markedwith a radiopaque marker. Fluoroscopy may be used to confirm that thedistal end of the inner tube 140 is positioned within the interior ofthe implantable device. If the inner tube 140 is not properlypositioned, the radiopaque marker facilitates viewing of the distal endof the inner tube 140 and thus adjustment of the inner tube 140 tosufficiently radially collapse the implantable device.

Alternatively, or in addition, a combination of radiopaque markers maybe provided on the repositioning device 100 as well as on theimplantable device. This may particularly be useful if one wishes toutilize fluoroscopy independent of an endoscope. For example, a portionof the drawstring of the implantable device may be marked with aradiopaque marker. The grasper 160 or elongated member 150 may be markedwith a radiopaque marker. In this way, an endoscope may not be required,as the entire repositioning procedure and the relevant parts which needto be guided during the repositioning procedure, are sufficientlydisplayed on a monitor.

FIG. 9A is a side view of a gastrointestinal implant device 900. Thegastrointestinal implant device 900 includes an elongated, open-ended,unsupported flexible sleeve or tube 902 having a first proximal openingand a second distal opening. Within the sleeve 902 is a passageway thatextends from the first proximal opening to the second distal opening fortransporting the chyme exiting the stomach. The surface of thepassageway (the interior surface of the implant device 900) is smooth toenable the chyme to easily pass through. The exterior surface of theimplant device 900 is smooth to prevent tissue in-growth and to benon-irritating to the bowel.

The sleeve material 902 is floppy, thin, and conformable so that itcollapses in the intestine to a small volume to minimize bowelirritability. Also, the sleeve 902 has minimal hoop strength, so that itcan fall flat until food passes through, thus minimizing interferencewith peristalsis. It has a low coefficient of friction (less than about0.20) so that chyme slides easily through it and the bowel slides easilyaround it. Further, the low coefficient of friction prevents the sleevefrom sticking to itself, thus making it easier for the sleeve 902 toopen as chyme is pushed through it. It is of low permeability to fluidsso that the chyme does not touch the bowel wall and the digestiveenzymes do not significantly breakdown the chyme. It is biologicallyinert and non-irritating to the tissues. One class of materials includesfluoropolymers. In some embodiments, the sleeve 902 is formed fromexpanded PTFE with a wall thickness of about 0.0005 to 0.001 inches andan internodal distance of 20 microns. This material is hydrophobic butis slightly porous. However, these very small pores may plug over time.The porosity may be reduced by coating the material on the inside,outside or in the pores with dilute solutions of silicone orpolyurethane.

Another material is polyethylene with a wall thickness of less than0.001 inches. Other materials include Cast PolyTetraFluoroEthylene(PTFE, e.g., TEFLON™), Cast PTFE with Fluorinated Ethylene Propylene(FEP) or PerFluoroAlkoxy (PFA) coating to minimize pin holes, ExtrudedFEP and Extruded PFA. These materials are solid and substantiallynon-porous in contrast to ePTFE which is porous, but these materials arealso considered to be fluoropolymers. The wall thickness is preferablyless than about 0.001 inches. Rubber-like materials typically havefriction coefficients of about 1-4, significantly stickier than thesematerials. However, in alternate embodiments other materials havingsimilar characteristics can be used.

In some embodiments, the sleeve 902 is formed using a combination of twoor more materials. For example, the sleeve 902 can be formed using acombination of ePTFE and FEP. Such a combination can be formed bylayering the two materials together and generally provides a lowcoefficient of friction while being substantially non-permeable. TheePTFE provides significant flexibility and softness while the FEP isused to seal the pores in the ePTFE making the material substantiallynon-porous. This material is used to form the sleeve as well as to coverboth the outer and inner surfaces of the anchor.

The sleeve 902 includes two layers of material at least at the proximalend. A first outer layer covers the exterior of the anchor 908. Thesecond inner layer covers the interior surface of the anchor 908. Thebarbs 275 protrude from the exterior surface of the anchor 908 throughthe first outer layer of the sleeve 902. The holes in the first outerlayer through which the barbs 275 protrude can be filled with animpervious material such as silicone or urethane to limit mixing ofdigestive juices with the chyme flowing through the passageway. Thediameter of the sleeve 902 is selected such that the first outer layerof the sleeve 902 fits over the anchor 908.

The sleeve length is variable and can range from about one foot to aboutfive feet. The typical length of the sleeve 902 is about 2 to 4 feetmeasured from the anchor (barbs 275) in the bulbous duodenum to belowthe ligament of Treitz. The length 912 of the sleeve 902 is selected tobypass the duodenum and a portion of the jejunum. The length canoptionally be increased to further decrease absorption by bypassing alonger section of the jejunum. Thus, the length of the sleeve 902 isvariable and may be dependent on the patient's Body Mass Index (BMI).The procedure is a less invasive alternative to surgery for thetreatment of obesity and morbid obesity and also provides a newtreatment approach for Type-2 diabetes.

Within the implant device 900 at the proximal end including the firstproximal opening is a collapsible self-expanding anchor 908. The anchor908 may be a collapsible self-expanding stent with struts.Alternatively, the anchor 908 may be a collapsible, self-expanding wavetype anchor coupled to the proximal portion of the sleeve 902 as shownhere. The wave anchor 908 includes adjacent interconnected struts 940connected by wave peak 950. In one embodiment, the anchor 908 has tenstruts.

The wave anchor 908 includes a compliant, radial spring shaped into anannular wave pattern, providing an outward radial force, while allowingsubstantial flexure about its perimeter. Such flexure is advantageous asit allows for minimally-invasive delivery and ensures that the devicewill substantially conform to the surrounding anatomical structure whenimplanted. The annular wave element can be formed from one or moreelongated resilient members and defines a lumen along its central axisformed between two open ends. When implanted, the central axis of theanchor 908 is substantially aligned with the central axis of theduodenum, allowing chyme to pass through the device 900. Additionally,the compliant wave anchor 908 minimizes trauma to the tissue byproviding sufficient flexibility and compliance, while minimizing thelikelihood of tissue erosion and providing a solid anchoring point tothe tissue.

The compliant wave anchor 908 can be manufactured from a resilient metalsuch as a heat-treated spring steel, stainless steel, or from an alloysuch as NiTi alloy commonly referred to as Nitinol. Other alloys includenickel-cobalt-chromium-molybdenum alloys possessing a unique combinationof ultrahigh tensile strength, such as MP35N. Additionally, the waveanchor 908 can be formed from a polymer and/or a composite havingsimilar properties. The wave anchor 908 can be manufactured from asingle strand, such as a wire, contoured into the desired shape.Alternatively, the wave anchor 908 can be manufactured frommulti-strands of the same or different materials similarly contoured tothe desired shape. In some embodiments, the wave anchor 908 can be cutinto the wave shape from tubular stock of the desired material, such asNitinol. The wave anchor 908 can be removably attached within the bodyusing any of the methods described herein for securing a anchor 908,including the use of barbs 275 attached to, and/or formed on the anchoritself. Preferably, the anchor 908 is radially collapsible forendoscopic insertion.

The wave anchor 908 includes webbing material 970 between the struts 940of the anchor 908. The webbing material 970 can be made of a class ofmaterials including fluoropolymers. In some embodiments, the webbingmaterial 970 is formed from expanded PTFE. Another material ispolyethylene. Other materials include Cast PolyTetraFluoroEthylene(PTFE, e.g., TEFLON™), Cast PTFE with Fluorinated Ethylene Propylene(FEP) or PerFluoroAlkoxy (PFA), Extruded FEP and Extruded PFA. Waveanchors are further described in U.S. application Ser. No. 11/299,392,filed on Sep. 16, 2005, claiming the benefit of U.S. ProvisionalApplication 60/611,038 filed on Sep. 17, 2004, herein incorporated byreference in their entireties.

The anchor 908 includes a plurality of opposed barbs 275 for anchoringthe implant device 900 to the muscular tissue of the duodenum. The barbs275 include pairs of rigid, elongated barbs. Each side of the pair,respectively side 920 and side 930 are outwardly directed at fixedangles and in opposite axial directions. The barbs are of a length suchthat they are able to penetrate muscular tissue.

Further details of the barbs 275 are shown in FIGS. 12A-12D. Each of thestruts 940 has one set of barbs with both proximal and distal facingpoints. The barbs 275 are made from a single piece of wire and arecrimped onto each strut 940 with a piece of stainless steel tubing. Thebarbs 275 are located at the proximal end of the anchor 908. Each barb275 is crimped such that the barb 940 is located on the inside of eachstrut 940 as shown in FIG. 12, that is, on the side facing the adjacentstrut intersecting at the proximal end. This minimizes the likelihood ofgetting adjacent struts 940 intersecting at the distal ends hooked ontothe barbs 275 during delivery when the anchor 908 is collapsed. Anend-on view of the anchor 908 with barbs 275 is shown in FIG. 12B. Aside view of the anchor 908 with barbs 275 is shown in FIG. 12C.

As shown in FIG. 12D, the proximally facing barbs 1220 are at least 2.0mm (0.080 inches) in height off the strut 940. The distal facing barbs1210 protrude at least 2.5 mm (0.10 inches) in height. If the barbs 275are shortened below roughly 1.5 mm, the implant migrates quickly. In oneembodiment, the proximal facing barbs 1220 are short so as to make iteasy to remove the device from the surrounding tissue, and to cover thebarbs 275 in the hood 190 as the device is removed from the body.

The distal facing barbs 1210 may be longer. Even though peristalsismoves the implant in both directions, the overriding force is to pullthe implant distal, thus the distal barbs need to be longer to hold thedevice in place within the muscle. The distal facing barbs 1210 may beup to 6 mm in height. There is a risk as they are made longer that theymay penetrate organs that are adjacent to the duodenum such as the liveror pancreas.

The uncompressed duodenal tissues are about 3 mm thick. When an anchoris placed in the duodenum, the inner diameter of the duodenum expands toaccommodate the anchor. As the inner wall expands, the duodenal wallthins to 1 to 2 mm in thickness. Therefore, proximal or distal barbswith a height higher than 2.0 mm may be useful to ensure that theypenetrate the muscularis. The reason barbs may be desired to have aheight greater than 2 mm is that the wall of the duodenum will thickenover time so that a shorter barb will end up further from the muscularwall. Piercing beyond the muscle layer is not inherently dangerous;omentum from the stomach area will tend to cover over and seal any sitesof penetration very quickly. Additionally, inflammatory cells willinvade the area to seal off any sites where penetration of the musclewall has occurred.

The barbs 275 are made of 0.020 inch diameter, nitinol wire making themquite stiff. The barbs are stiff enough to not be deflected by the softtissues within the gastrointestinal tract. It takes about 1 lb of forceper barb to deflect from 40 degrees to 90 degrees. The range ofdiameters that could be effectively utilized in nitinol would be 0.005″to about 0.030″. Any diameter smaller than 0.005″ results in a floppybarb that does not resist deflection well. Beyond a diameter of 0.030″,barbs are so stiff that collapsing the anchor into a small tube fordelivery becomes exceeding difficult.

They are made of nitinol to facilitate elastic bending when they areloaded into the delivery capsule. The angle of each barb 275 to theanchor strut 940 is about 40 degrees. This angle could vary from about20 degrees to about 90 degrees.

The diameter of the anchor 908 is dependent on the diameter of theduodenum, that is about 1.0″ to 2.5″ based on human anatomy variations.The anchor is adapted to be retained within the duodenum, particularlyin the duodenal bulb just distal to the pylorus. In one embodiment, thelength of 1 inch of the anchor 908 is selected to reside within thebulbous duodenum. In the current embodiment, the length of the anchor is32 mm while the relaxed diameter is 53 mm.

The intraluminal anchor can also include the drawstring 280 aspreviously described, to facilitate repositioning and/or removal. Thedrawstring 280 can be provided at a proximal end of the implant device900 and be adapted for engagement by a removal device such as a hook.The drawstring 280, when engaged, can be pushed or pulled by the removaldevice, in opposition to the stationary intraluminal anchor, to at leastpartially collapse at least part of the intraluminal anchor. With areduced diameter, the device can be removed through, or repositionedwithin, the natural bodily lumen. In some embodiments, at least aportion of the device is drawn into a retrieval hood, sheath, orovertube prior to removal as shown in FIGS. 2A-2F.

The drawstring 280 is shown woven through pairs of eyelets 980 distal tothe wave peak 950 in the webbing material 970. The implantable device900 can also include a second drawstring 990 distal to drawstring 280.This drawstring can also be woven through pairs of eyelets 995 distal toeyelets 980 for drawstring 280. The second drawstring 990 is analternative drawstring in the situation that the first drawstring 280breaks during repositioning or removal.

FIG. 9B illustrates an alternative embodiment of the weaving of thedrawstrings 280 and 990. The drawstring 280 is woven through a singleeyelet 985 in the webbing material 970, and over and under respectivestruts 940. The second distal drawstring 990 can be threaded throughpairs of eyelets 995 as described in FIG. 9A or alternatively can alsobe threaded through an additional single hole 996 distal to the hole 985for the drawstring 280.

FIGS. 9C and 9D shows an embodiment of threading the proximal drawstring280 as is illustrated in FIG. 9B. The second drawstring 990 is however,threaded through a pair of holes 995. The advantage of the approach ofFIGS. 9A-9C is demonstrated by comparison of FIGS. 10A and 10B withFIGS. 11A and 11B.

FIG. 10A and 10B illustrate the approach of FIG. 9A. In operation, thedrawstring 280 can be pulled by the retrieval device 1060 (such as theone shown in FIG. 1) as shown in FIG. 10A. The drawstring 280, whenpulled, contracts about the perimeter of the anchor 908, therebyreducing the diameter of the anchor 908. Thus, the drawstring 280 can beused to facilitate removal of an implanted anchor 908 by pulling it awayfrom the surrounding anatomy thereby extracting any barbs 275 from thesurrounding muscular tissue.

Because the anchor 908 is positioned distal to the pylorus within theduodenal bulb as shown in FIG. 3A, the anchor 908 is at an angle withrespect to the pylorus. When the retrieval device 1060 pulls on thedrawstring 280, the webbing material 970 is pulled inward between thestruts since the eyelets 980 are distal to the struts 940 on the webbingmaterial 970. As the drawstring 280 is drawn, the tip of the retrievaldevice 1060, already angled relative to the anchor 908, can be caughtbetween a pair of struts 940 rather than between all of the wave peaks950. In that case, the retrieval device may become cocked between twostruts 940 within the collapsed anchor 908. As a result, the collapsedanchor 908 has limited degrees of freedom relative to the retrievaldevice 1060 and can not pivot and straighten with respect to the pylorusand is thus removed at an angle with respect to the pylorus. If thedrawstring 280 is not released and reengaged it becomes difficult topull the barbs 275 into the hood 190 (as shown in FIGS. 2A-2F.) This canresult in damage to surrounding tissue since the collapsed anchor 908with barbs 275 is dragged through the intestine and pylorus sideways.Further, the esophagus is an extremely delicate area and dragging theanchor sideways with its protruding barbs could result in injury to thepatient.

Additionally, pulling hard on the webbing material 970 by the retrievaldevice 1060 in an attempt to fully pull it into the hood 190 could causetearing of the webbing material 970. Further, pulling on the webbingmaterial 970 with the retrieval device 1060 to one side does not fullyand uniformly collapse the anchor 908 as can be seen in the end on viewof the anchor in FIG. 10B. A gap 1090, often results from this pulladding to the difficulty of pulling all of the barbs 275 into the hood190.

FIGS. 11A-11B shows an embodiment of threading the proximal drawstring280 as was illustrated in FIGS. 9B-9D. The weaving of the drawstring 280through the single hole 985 and over and under the alternate struts 940on the proximal end of the anchor 908 near the wave peaks 950 allows thestruts 940 to be pulled as opposed to the webbing material 1070, as wasthe case in FIG. 10A. Also, the single hole 985 can be made immediatelyadjacent to the wave peaks 950. In operation, when the retrieval device1060 pulls on the proximal drawstring 280 in order to collapse theanchor, it remains proximal to wave peaks 950 of the anchor 908 on theoutside of the anchor 908, as shown in the end-on view of the anchor inFIG. 11B.

This in turn allows increased degrees of freedom for the collapsedanchor 908 relative to the retrieval device 1060, since the retrievaldevice 1060 is not cocked between two struts 940. The anchor 908 cantherefore, pivot and straighten itself with respect to the hood 190 inthe pylorus as it is pulled into the hood.

Further, because the wave peaks 950 are pulled, as opposed to thewebbing material 970, there results a more complete and uniform collapseas shown in FIG. 11D. The fuller collapse as well as the straighteningof the anchor 908 allows for the anchor 908 and barbs 275 to be easilycaptured by a capturing mechanism, such as the flared hood 190. Thisreduces the risk of damage to surrounding tissue since the collapsedanchor 908 can be dragged out of the body straight through thegastrointestinal tract with at least the proximally directed barbs 275fully enclosed in the hood 190.

Additionally, the pulling of the wave peaks 950 as opposed to webbingmaterial 970, makes the tearing the webbing material 970 less likely andinconsequential. The greater strength of the suture material forming thedrawstrings 280 and 990 now becomes the weakest link in the retrievalsystem.

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and detail may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

1. A gastrointestinal implant device comprising: a flexible, floppysleeve, open at both ends, to extend into the duodenum; a collapsibleanchor coupled to a proximal portion of the sleeve; a drawstringthreaded through a proximal end of the anchor; and rigid barbs extendingfrom the exterior surface of the anchor at fixed angles.
 2. The implantof claim 1, wherein the anchor comprises interconnected struts with awebbing material being coupled to the struts.
 3. The implant of claim 1,wherein the anchor is a wave anchor.
 4. The implant of claim 3, whereinthe drawstring is woven over and under the struts.
 5. The implant ofclaim 4, further comprising a second drawstring that is woven over andunder the struts.
 6. The implant of claim 4, further comprising a seconddrawstring that is woven through pairs of holes between the struts. 7.The implant of claim 1, wherein the sleeve is at least one foot inlength.
 8. The implant of claim 1, wherein the barbs penetrate muscle.9. A method of repositioning a gastrointestinal device within a naturalbodily lumen comprising: engaging a drawstring disposed on theimplantable device, the implantable device comprising; flexible, floppysleeve, open at both ends, to extend into the duodenum; a collapsibleanchor coupled to a proximal portion of the sleeve; the drawstringthreaded through a proximal end of the anchor; and barbs extending fromthe exterior surface of the anchor; collapsing at least a proximalportion of the implantable device by pulling the drawstring; and movingthe implantable device within the natural bodily lumen.
 10. The methodof claim 9, wherein the anchor comprises interconnected struts with awebbing material being coupled to the struts.
 11. The method of claim10, wherein the anchor is a wave anchor.
 12. The method of claim 11,wherein the drawstring is woven over and under the struts.
 13. Themethod of claim 12, further comprising a second drawstring that is wovenover and under the struts.
 14. The method of claim 12, furthercomprising a second drawstring that is woven through pairs of holesbetween the struts.
 15. The method of claim 9 wherein the sleeve is atleast one foot in length.
 16. The method of claim 9, wherein therepositioning comprises removing the implantable device from thepatient's body.
 17. The method of claim 9, wherein the barbs penetratemuscle.